F.1 Maths 快快快快!!! 20點!

2011-12-05 12:27 am

1. If N number of $50 notes can be exchanged for C number of 20 ₡ coins, then the relation between C and N can be expressed by the formula C = 250N. How many 20₡ coins can be exchanged for four $50 notes?

2.It is known that the monthly service charge $C of a moblie phone can be calculated by the formula C= 80+1.2m, where m is the ectra talking time( in minutes) in that month
a) Find the monthly service charge of the moblie phone if Allen's extra talking time in this month is 40 minutes.
b) If Bobby has to pay $110 for the monthly service charge of his moblie in this monthly. find his extra talking time.

回答 (2)

用戶50068

2011-12-05 12:51 am

✔ 最佳答案

洗5洗STEPS,要STEP LATER俾.
1.250*5=1250
2a)c=80+1.2m
C=80+1.2(40)
c=80+48
c=128
b)110=80+1.2m
1.2m=30
m=25

明5明?5明可以再問..~^^~

2011-12-04 16:51:55 補充：
第1題打錯左,系250*4=1000

參考: ME

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[匿名]

2011-12-05 12:43 am

1.250
2.sorry I don't know

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